Reference#: P01620

A radar system that can rapidly detect and reliably identify targets such as concealed weapons and electronics. Persons either walking through a fixed portal/doorway or walking or congregating in a foyer, entranceway or other open area can carry the targets. The systems needs to be able to achieve a high probability of detection with a low false alarm rate and automatically discriminate between weapons, electronic assemblies and clutter.

The Johns Hopkins Applied Physics Laboratory has developed and patented a system for detecting concealed weapons, electronics, and other man-made objects. APL's system is a harmonic radar nonlinear junction detector. The system uses state-of-the art wireless technology, circuit fabrication, signal synthesis, and computer processing techniques to detect and characterize man-made objects possessing nonlinear junctions.
There are certain non-linear impedance characteristics that are an inherent property of man-made objects that contain metal-to-metal, semiconductor-to-semiconductor, and metal to semiconductor interfaces. When such man-made objects are illuminated by an electromagnetic signal, the rectification properties of the nonlinear impedances cause new signals to be generated at frequencies that are exact multiples of the frequency of the original signal. These new signals are radiated, and can be detected with super heterodyne receiver like that used in conventional radars.